/Engine/Source/Runtime/Engine/Classes/Kismet/GameplayStatics.h
Sets the max number of voices (also known as "channels") dynamically by percentage. E.g. if you want to temporarily reduce voice count by 50%, use 0.50. Later, you can return to the original max voice count by using 1.0.
static void SetMaxAudioChannelsScaled ( const [UObject](API\Runtime\CoreUObject\UObject\UObject) * WorldContextObject, float MaxChannelCountScale )